The correct option is D plerome
Plerome is the central core of primary meristem of a plant or plant part that gives rise to the vascular tissues.
Periblem is part of the primary meristem that gives rise to the cortex and is located between plerome and dermatogen.
Dermatogen is the outer primary meristem of a plant or plant part that gives rise to the epidermis.
Phellogen, also known as cork cambium is a secondary meristem that initiates phellem and phelloderm in the periderm of a stem or root.